package com.binarytree;

public class Solution12 {
    public boolean isBalanced(TreeNode root) {
        return getHeight(root) != -1;
    }

    public int getHeight(TreeNode root) {
        if (root == null) return 0;

        int leftHeight = getHeight(root.left);
        if (leftHeight == -1) return -1;
        int rightHeight = getHeight(root.right);
        if (rightHeight == -1) return -1;
        if (Math.abs(leftHeight-rightHeight) > 1) return -1;
        return Math.max(leftHeight,rightHeight)+1;
    }
}
